No need to replace coolant other than that you loose during the replacement process (minimal usually)
I wound be asking Steve at MB Edinburgh for a quote. Items like this are crucial for the correct running of the engine so it is good to have the OE part.
Thank you for an interlugeht and well constructed response as ever.
I agree entirely with your comments except for the inevitability that engines will choke up with carbon over time if you do not use additives.
A lot will depend on the engine design, and how it is used and looked...
What do you want to read? Just OBD codes or more manufacturer specific codes?
The search function on the Forum will almost certainly give you lots of information, if it is just OBD then the "Torque" App works well and you can use a cheap Bluetooth OBD reader to transmit data back to your...